The present invention relates to a breechblock mechanism for a gun. More particularly, the present invention relates to a breech mechanism which is displaceably arranged within a parallel guideway disposed in the gun barrel breech ring at a right angle to the bore axis of the gun barrel, and which is provided with means for obturation which are movable transversely to the direction of displacement within the guideway.
In such a breech mechanism, as it is disclosed in EP 00 14 559, it is necessary to seal the chamber by bringing a mushroom shaped head of the breech mechanism in a partial arc to the charge chamber. For this purpose, it is necessary to provide roller guides, a coupling rod assembly and, in addition, stages for determining the "open" and "closed" breech positions, with such stages being disposed in a driving member. Due to the large number of driving means for the mushroom head, complicated motion sequences result within the breech system which may lead to increased susceptibility to malfunction and do not permit high firing rates.
The book by Rheinmetall, entitled "Waffentechnisches Taschenbuch" [Handbook on Weaponry] 6th Edition, 1983, page 313, FIG. 862, also discloses the sealing of the chamber against the breech wedge by means of a steel obturator ring.
However, this breech wedge does not permit the use of elastically deformable ring obturators containing high percentages of plastics as disclosed, for example, in U.S. Pat. No. 1,460,683 instead of the steel obturator ring because, due to the simultaneous radial and axial direction of movement of the breech wedge and a greater sealing stroke required to tension the elastically deformable ring obturator, it is possible for the breech wedge to move in a way which enhances wear of the seal. Moreover, if, for example, a sealing ring as disclosed in U.S. Pat. No. 1,460,683 is employed, no long-term sealing effect can be realized for such an application because the elastically deformable sealing ring is able to escape toward the chamber due to the absence of a support in the interior.
In contrast thereto, it is an object of the invention to improve the prior art breech mechanism of the type including a breechblock which is displaceably guided in a parallel guideway disposed in the gun barrel breech ring at a right angle to the bore axis of the gun barrel and which is provided with means movable transversely to the displacement direction for obturation so that a reliable and durable seal can be obtained at high firing rates for elastically deformable ring obturators which are fixed to the end of the gun barrel, with such seal being obtained by simple kinematics and a robust support within the breech mechanism.